Most personal navigation systems exist as hand-held devices which report position in terns of latitude, longitude, and altitude. Primitive mapping functions are usually provided that display the path that a user has followed or provide a simple steering indication to facilitate taking a straight line path towards a desired coordinate. More sophisticated systems may include low resolution map information upon which the users coordinates are overlaid.
There are several problems with these existing systems. First, the use of LCD-type displays makes these devices virtually unusable in direct sunlight because of insufficient display contrast. Second, because the storage of detailed images requires large amounts of data storage, map resolution is limited. Third, because of these storage limitations and because of the difficulty of obtaining accurate map data, the selection of maps for users to exploit is very small.
Addressing these issues requires a device which makes improvements in two fundamental areas. First, a new display system is needed which will allow the user to see presented images clearly in all lighting conditions. Second, improvements in data storage must be made to allow the user to store a meaningful amount of high accuracy data.